Are you at risk of failing a roadside drug test after a wild weekend?
If you took party drugs or smoked cannabis on the weekend, would you fail a drug test on Monday? A forensic toxicologist reveals all.
Before we tell you the answer, let's make one thing extremely clear...
NEVER DRIVE IF YOU ARE UNDER THE INFLUENCE OF DRUGS OR ALCOHOL
With a 'saliva test' drugs can no longer be detected approximately 12-24 hours after consumption.
“It’s important to know that different tests have different periods of detection,” Forensic Toxicologist, Mr Leibie said.
“Urine testing typically can detect drugs in the body for much longer than saliva tests.
“And blood testing is different again but it’s the saliva testing that police do in roadside tests so the drugs are only detected while they’re still psychoactive.”
Mr Leibie said the length of time illicit drugs remained in each user’s system varied from one individual to another but that it was “extremely rare” for cannabis or methamphetamine to be detected on roadside screenings days or weeks after being consumed, when the drug was no longer psychoactive.
“It’s hard to talk generally because every individual’s metabolism and health status is different as well as the amount of the drug they’ve consumed,” he said.
“But if we’re talking — someone takes a drug on Saturday night and gets a saliva test on Monday morning — it’s very, very unlikely they’ll get a positive result, but theoretically not impossible.”
A saliva drug test is deemed positive under the current Australian oral drug testing standards (AS 4760) for readings of or above 25 nanograms per milligram of THC (the active ingredient in cannabis) or 50 nanograms per milligram for methamphetamine, including MDMA.
Saliva tests are currently used in various Australian states and territories to detect illicit drugs but are not yet used to screen for many prescription drugs, including benzodiazepines, which can impair drivers.
“Saliva testing is a bit like breathalysers,” Mr Leibie said.
“Generally speaking, cannabis usually won’t be detected after 12 hours but if someone is smoking a large amount regularly it might be up to 24 hours in extreme cases but in most cases it would be normal to not show up after five to six hours.
“For ecstasy and ice, which are all a part of the methamphetamine group, we’re fairly confident saliva testing will detect the drugs for up to 24 hours or 36 hours in absolute extreme environments where there might be confusion or liver damage.
“What they’re looking for in a saliva test is the active drug — the part of the drug that’s psychoactive that’s causing effect.
“In the urine test we’re looking for the metabolised drug — after the drug has been consumed and your liver has changed the drug and excreted in urine — and that takes time to occur.”
Mr Leibie said it was not yet known how long new drugs on the market, including flakka and synthetic cannabis, stayed in a user’s system.
“We know these drugs, cannabis and methamphetamine; have a very deleterious effect on your driving performance,” Mr Leibie said.
“No doubt they will have an effect and impact on their ability to drive safely.
“But what we can’t say is that by taking the drugs it means the user is impaired.
“A roadside drug test alone cannot be considered evidence of impairment. Police collect a saliva sample and that goes back to the lab which is built around Australian standards.
“There’s a big push from unions for workplace drug testing to be saliva testing instead of urine is because then the results aren’t about what the person did on the weekend. They’re only about whether or not workers are at risk or going to impact others.”
More than 97,000. roadside drug tests are carried out in NSW each year.